Prepare for and practice interview questions from Commonwealth Bank.

Commonwealth Bank Interview Questions

Commonwealth Bank Interview Guides

Data Structures & Algorithms

Given two sorted lists, write a function to merge them into one sorted list.

Merge Sorted Lists

Find the missing integer from a array of consequtive integers

Find the Missing Number

Get Top N Frequent Words

Write a function to return the cumulative percentage of students that received scores within certain buckets.

Bucket Test Scores

String Shift

Write a query to select the top 3 departments with at least ten employees and rank them according to the percentage of their employees making over 100K in salary.

Employee Salaries

Select the 2nd highest salary in the engineering department

2nd Highest Salary

Write a SQL query to create a histogram of the number of comments per user in the month of January 2020.

Comments Histogram

Write a query that returns all neighborhoods that have 0 users.

Empty Neighborhoods

Closest SAT Scores

Machine Learning

Encoding Categorical Features

Coefficients of Logistic Regression

Booking Regression

Bank Fraud Model

Rebalancing outcome probabilities for a classifier on imbalanced data.

Rebalance Probabilities

Probability

500 Cards

Given three uniform(0,4) random variables, what is the probability that the median of them is greater than 3?

Median Probability

Flipping 576 Times

Profit-Maximizing Dice Game

Mutated Offspring

Statistics

P-value to a Layman

Estimating D

What are the assumptions of linear regression?

Assumptions of Linear Regression

What is the difference between the Z and t tests?

Z and t-Tests

Compute Variance

When an interviewer asks a question along the lines of:

<ul>
<li>What would your current manager say about you? What constructive criticisms might he give?</li>
<li>What are your three biggest strengths and weaknesses you have identified in yourself?</li>
</ul>

How would you respond?

When asked about your strengths in an interview, what is an effective way to respond?

When asked about your strengths in an interview, what is an effective way to respond?

Your Strengths and Weaknesses I

Which of the following is an acceptable strategy when discussing weaknesses in an interview?

Which of the following is an acceptable strategy when discussing weaknesses in an interview?

Your Strengths and Weaknesses II

What do you tell an interviewer when they ask you what your strengths and weaknesses are?

Your Strengths and Weaknesses

Brainteasers

When an interviewer asks you a question along the lines of:

<ul>
<li>Why did you apply to our company?</li>
<li>What are you looking for in your next job?</li>
<li>What makes you a good fit for our company?</li>
</ul>

How should you respond?

When asked 'What are you looking for in your next job?' in an interview, how can you tie the company's employee benefits into your response?

When asked 'What are you looking for in your next job?' in an interview, how can you tie the company's employee benefits into your response?

Why Do You Want to Work With Us I

How can company values be used effectively in an interview when asked 'What makes you a good fit for our company?'

How can company values be used effectively in an interview when asked 'What makes you a good fit for our company?'

Why Do You Want to Work With Us II

When responding to the question 'Why did you apply to our company?' during an interview, what aspect should you highlight?

When responding to the question 'Why did you apply to our company?' during an interview, what aspect should you highlight?

Why Do You Want to Work With Us III

How would you answer when an Interviewer asks why you applied to their company?

Why Do You Want to Work With Us

Describe a data project you worked on. What were some of the challenges you faced?

Describing a data project and its challenges

Hurdles In Data Projects

Analytics

How would you explain what a p-value is to someone who is not technical?

What does a p-value in a statistical test represent?

What does a p-value in a statistical test represent?

P-value to a Layman I

In a statistical test, how does a low p-value (less than 0.05) influence our decision about the null hypothesis?

In a statistical test, how does a low p-value (less than 0.05) influence our decision about the null hypothesis?

P-value to a Layman II

What are the assumptions of linear regression?

Which assumption of the residuals of the standard linear regression model can not be overcome by increasing the sample size?

Regression assumptions

Let’s say that you’re training a classification model.

How would you combat overfitting when building tree-based models?

Let's say that you're training a classification model.   How would you combat overfitting when building tree-based models?

Overfit Avoidance

Tell me about a project in which you had to clean and organize a large dataset.

Describing a real-world data cleaning and organization project

Data Cleaning Experiences

Data Pipelines

How would you handle the data preparation for building a machine learning model using imbalanced data?

Addressing imbalanced data in machine learning through carefully prepared techniques.

Data Preparation for Imbalanced Data

Let’s say we’re comparing two machine learning algorithms. In which case would you use a bagging algorithm versus a boosting algorithm? 

Give an example of the tradeoffs between the two.

In machine learning, when would you use a bagging algorithm over a boosting algorithm?

In machine learning, when would you use a bagging algorithm over a boosting algorithm?

Bagging vs. Boosting

Bagging vs Boosting

Given a string, write a function to determine if it is palindrome or not.

Note: A palindrome is a word/string that is read the same way forward as it is backward, e.g. <code>&#39;reviver&#39;</code>, <code>&#39;madam&#39;</code>, <code>&#39;deified&#39;</code> and <code>&#39;civic&#39;</code> are all palindromes, while <code>&#39;tree&#39;</code>, <code>&#39;music&#39;</code> and <code>&#39;person&#39;</code> are not palindromes.

Example:

Input:

<pre tabindex="0" class="chroma"><code>word1 = &#34;tree&#34;
word2 = &#34;radar&#34;
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>def is_palindrome(word1) -&gt; False
def is_palindrome(word2) -&gt; True
</code></pre>

Given a string, write a function to determine if it is palindrome or not.

String Palindromes

Write a SQL query to select the 2nd highest salary in the engineering department.

Note: If more than one person shares the highest salary, the query should select the next highest salary.

Example:

Input:

<code>employees</code> table

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>first_name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>last_name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>salary</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>department_id</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<code>departments</code> table

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>name</code></td>
<td>VARCHAR</td>
</tr>
</tbody>
</table>
Output:

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>salary</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>

Imagine you are asked to build a machine learning model to decide new loan approvals for a
financial firm. You ask the data department in the company for a subset of data to get started
working on the problem. The data includes different features about applicants such as age,
occupation, zip code, height, number of children, favorite color, etc. You decide to build
multiple machine learning models to test out different ideas before settling on the best one.

How would you explain the bias-variance tradeoff with regards to
building and choosing a model to use?

Bias vs. Variance Tradeoff

Explain the difference between the XGBoost and random forest algorithms and give an example where you would use one over the other.

Why might a data scientist choose to use XGBoost instead of Random Forest for a particular machine learning task?

Why might a data scientist choose to use XGBoost instead of Random Forest for a particular machine learning task?

XGBoost vs Random Forest: Choice

Xgboost vs Random Forest

What is the difference between Logistic and Linear Regression?

When would use one instead of the other in practice?

What is the difference between Logistic and Linear Regression?

Linear vs Logistic Regression

Let’s say that you work at a B2B SAAS company that’s interested in testing the pricing of different levels of subscriptions.

Your project manager comes to you and asks you to run a two-week-long A/B test to test an increase in pricing.

How would you approach designing this test? How would you determine whether the increase in pricing is a good business decision?

Testing Price Increase

A/B Testing

Create a class named <code>LRUCache</code> that implements the behavior expected of a Least Recently Used (LRU) Cache.

The <code>LRUCache</code> class implements the following methods:

<ul>
<li><code>__init__(self, capacity)</code> - initializes the object and takes in a capacity parameter specifying the maximum capacity of the cache.</li>
<li><code>get_if_exists(self, key) -&gt; Any|None</code> - gets a value based on a key. If the key exists, returns the associated value. If the key has expired or did not exist in the first place, returns <code>None</code>.</li>
<li><code>put(self, key, value)</code> - places a value inside the cache. In the case wherein the cache is full, invalidates the least recently used element. When two keys collide, the older value should be invalidated in place of the new one.</li>
</ul>

Example:

<pre tabindex="0" class="chroma"><code>cache = LRUCache(2)
cache.put(&#34;sample&#34;, 55)
cache.get_if_exists(&#34;sample&#34;) # returns 55
cache.get_if_exists(&#34;key&#34;) # returns None
cache.put(&#34;hello&#34;, 10) 
cache.put(&#34;sample&#34;, 9)
cache.put(&#34;world&#34;, 5)
cache.get_if_exists(&#34;hello&#34;) # returns None
</code></pre>

Notes:

<ul>
<li>It is assured that the value in the <code>put</code> method will never receive a <code>None</code> value. Moreover, it is assured that the capacity will always be &gt; 0.</li>

<li>All operations must be O(1).</li>

<li>Aside from Python’s standard dictionary implementation (<code>{}</code>), you may not use any other built-in data structures.</li>
</ul>

LRU Cache 1

Let’s say we want to launch a re-design of a landing page to improve the click-through rate. We can do this by implementing an AB test.
Given that we launch an AB test, how would you infer if the results of the click-through rate were statistically significant or not?

How can you accurately conclude if the results of an A/B test, conducted to evaluate the effectiveness of a landing page redesign, are statistically significant?

How can you accurately conclude if the results of an A/B test, conducted to evaluate the effectiveness of a landing page redesign, are statistically significant?

Statistically Significant Test

Precisely ascertain whether the outcomes of an A/B test, executed to assess the impact of a landing page redesign, exhibit statistical significance.

What are the key differences between classification models and regression models?

What is the MOST important difference between regression and classification models?

What is the MOST important difference between regression and classification models?

Classification vs Regression

Classification and Regression

Given an array and a target integer, write a function <code>sum_pair_indices</code> that returns the indices of two integers in the array that add up to the target integer. If not found, just return an empty list.

Note: Can you do it on \(O(n)\) time?

Note: Even though there could be many solutions, only one needs to be returned.

Example 1:

Input:

<pre tabindex="0" class="chroma"><code>array = [1 2 3 4] 
target = 5 
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>def sum_pair_indices(array, target) -&gt; [0 3] or [1 2]
</code></pre>

Example 2:

Input:

<pre tabindex="0" class="chroma"><code>array = [3]
target = 6 
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>Do NOT return [0 0] as you can&#39;t use an index twice.
</code></pre>

Given an array and a target integer, write a function that returns the indices of two integers in the array that add up to the target integer.

Target Indices

Let’s say that your company is running a standard control and variant AB test on a feature to increase conversion rates on the landing page. The PM checks the results and finds a .04 p-value.

How would you assess the validity of the result?

Experiment Validity

Let’s say that you work at a bank that wants to build a model to detect fraud on the platform.

The bank wants to implement a text messaging service in addition that will text customers when the model detects a fraudulent transaction in order for the customer to approve or deny the transaction with a text response.

How would we build this model?

Let’s say that you work at a bank that wants to build a model to detect fraud on the platform.

The bank wants to implement a text messaging service that will text customers when the model detects a fraudulent transaction in order for the customer to approve or deny the transaction with a text response.

Which statement is true?

Let's say that you work at a bank that wants to build a model to detect fraud on the platform.

The bank wants to implement a text messaging service that will text customers when the model detects a fraudulent transaction in order for the customer to approve or deny the transaction with a text response.

Which statement is true?

Let’s say you work at Allstate. Allstate is running <code>N</code> online ads right now. The table <code>ads</code> contains all those ads, ranked by popularity via the <code>id</code> column (e.g., the entry with <code>id = 1</code> is the most popular, etc.).

Create a subquery or common table expression named <code>top_ads</code> containing the top 3 ads (by popularity) and return the number of rows that would result from the following operations

<ol>
<li><code>ads INNER JOIN top_ads</code></li>
<li><code>ads LEFT JOIN top_ads</code></li>
<li><code>ads RIGHT JOIN top_ads</code></li>
<li><code>ads CROSS JOIN top_ads</code></li>
</ol>

Note: Please make the <code>join_type</code> column in your output have the values <code>inner_join</code>, <code>left_join</code>, etc. for each of their respective join types

Note: Please return only one query with each number in a different row

Example:

Input:

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>name</code></td>
<td>VARCHAR</td>
</tr>
</tbody>
</table>
Output:

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>join_type</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>number_of_rows</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>

Size of Joins

Given an integer <code>N</code>, write a function that returns a list of all of the prime numbers up to <code>N</code>.

Note: Return an empty list there are no prime numbers less than or equal to <code>N</code>.

Example:

Input:

<pre tabindex="0" class="chroma"><code>N = 3
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>def prime_numbers(N) -&gt; [2,3]
</code></pre>

Given an integer N, write a function that returns all of the prime numbers up to N

Prime to N

Regularization and cross-validation are two common techniques used to improve the performance of machine learning algorithms.

When should you use one versus the other?

Given the choices below, which one is an example of a scenario where we should be using regularization?

Given the choices below, which one is an example of a scenario where we should be using regularization?

Regularization Example

Regularization and Validation

What’s the difference between Lasso and Ridge Regression?

Under what circumstances is it recommended to use Lasso regression over Ridge regression?

Under what circumstances is it recommended to use Lasso regression over Ridge regression?

Lasso vs Ridge

<h1>Binary Tree Validation</h1>

You are given the root of a binary tree. You need to determine if it is a valid binary search tree (BST).

A valid BST is defined as follows:

<ul>
<li>The left subtree of a node contains only nodes with values less than or equal to the node’s value.</li>
<li>The right subtree of a node contains only nodes with values greater than or equal to the node’s value.</li>
<li>Both the left and right subtrees must also be binary search trees.</li>
</ul>

Given the function <code>def is_valid_bst(root: Node) -&gt; bool:</code>, return True if the binary tree is a valid BST. Otherwise, return False.

<h3>Example:</h3>

Input:

<img src="https://d2qpirhrfplx04.cloudfront.net/9664817c-3e12-4a40-9236-8382b13f55a0.png" alt="image"/>Converted Binary Tree.png

Output:

<pre tabindex="0" class="chroma"><code>def is_valid_bst(Node(3)) -&gt; True
</code></pre>

Given the root node, verify if a binary search tree is valid or not.

Binary Tree Validation

How would you convey insights and the methods you use to a non-technical audience?

Making data-driven insights actionable for those without technical expertise

Simple Explanations

Let’s say you are working on Google Docs. A product manager comes to you and asks how the product is doing. 

What are the top five metrics that you would start tracking to understand the health of Google Docs?

Docs Metrics

Product Sense & Metrics

The Fibonacci sequence is a series of numbers in which each number is the sum of the two preceding ones, usually starting with 0 and 1. It is often used in algorithm examples, and is defined by the following formula: F(n) = F(n-1) + F(n-2), with F(0) = 0 and F(1) = 1.

Your task is to implement the Fibonacci algorithm in three different methods:
1. Recursively
2. Iteratively
3. Using Memoization

Example 1:

Input:

<pre tabindex="0" class="chroma"><code>n = 5
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>fibonacci(n) -&gt; 5
</code></pre>

Example 2:

Input:

<pre tabindex="0" class="chroma"><code>n = 10
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>fibonacci(n) -&gt; 55
</code></pre>

The Fibonacci sequence starts as follows: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55…

This question requires the implementation of the Fibonacci sequence using three different methods: recursively, iteratively, and using memoization.

Implementing the Fibonacci Sequence in Three Different Methods

Let’s say you’re a data engineer at Fidelity Investments, and you’re running a SQL query on a cloud-based data warehouse. All cluster resources and network health metrics look normal, but the query is still taking over 10 minutes to complete.

How would you go about diagnosing and improving the performance of this query?

How would you diagnose and speed up a slow SQL query when system metrics look healthy?

Slow SQL Query

Query Optimization

Challenge

Organization: At CommBank, we never lose sight of the role we play in other people’s financial wellbeing. Our focus is to help people and businesses move forward to progress. To make the right financial decisions and achieve their dreams, targets, and aspirations. Regardless of where you work within our organisation, your initiative, talent, ideas, and energy all contribute to the impact that we can make with our work. Together we can achieve great things. Job Title: Principal Data Engineer Location: Bangalore Business & Team:The Technology Team is responsible for the world-leading application of technology and operations across every aspect of CommBank, from innovative product platforms for our customers to essential tools within our business. We also use technology to drive efficient and timely processing, an essential component of great customer service. CommBank is recognised as leading the industry in IT and operations with its world-class platforms and processes, agile IT infrastructure, and innovation in everything from payments to internet banking and mobile apps.The Group Security (GS) team protects the Bank and our customers from cyber compromise, through proactive management of cyber security, privacy, and operational risk. Our Group Security Data Engineering team leads the way to adopt the Group’s new strategic cloud data platform CommBank. Data. On this platform we are accountable for driving Group Security’s data driven and proactive security function through advanced analytics and agentic AI workflows. Impact & Contribution:To ensure the Group achieves a sustainable competitive advantage through data engineering, you will play a key role in supporting and executing the Group Security’s data strategy. In this role, you will be responsible for setting up the Group Security Data Platform to ingest data from various organizations' security telemetry data, along with additional data assets and data products. This platform will provide security controls and services leveraged across the Group. Roles & Responsibilities:You will be expected to perform the following tasks in a manner consistent with CBA’s Values and People Capabilities. Core Responsibilities:<ul><li>Possesses hands-on technical experience working in AWS.</li><li>The individual should possess a robust set of technical and soft skills and be an excellent AWS Data Engineer with a focus on complex Automation and Engineering Framework development.</li><li>Being well-versed in Python is mandatory, and experience in developing complex frameworks using Python is required.</li><li>Passionate about Cloud/DevSecOps/Automation and possess a keen interest in solving complex problems systematically.</li><li>Drive the development and implementation of scalable data solutions and data pipelines using various AWS services.</li><li>Possess the ability to work independently and collaborate closely with team members and technology leads.</li><li>Exhibit a proactive approach, constantly seeking innovative solutions to complex technical challenges.</li><li>Can take responsibility for nominated technical assets related to areas of expertise, including roadmaps and technical direction.</li><li>Can own and develop technical strategy, overseeing medium to complex engineering initiatives.</li><li>Lead the design and architecture of large-scale data systems, ensuring they meet business needs and performance requirements.</li><li>Provide strategic direction for data engineering initiatives, aligning them with organizational goals.</li><li>Mentor and guide senior data engineers, fostering a culture of continuous improvement and innovation.</li><li>Collaborate with executive leadership to define and prioritize data engineering projects.</li><li>Ensure the implementation of best practices in data management, security, and governance.</li><li>Act as a System and Data Architect, designing and implementing robust, scalable, and efficient data architectures.</li><li>Demonstrate capabilities to work in a fast-paced, high-pressure environment while delivering high-quality results on time.</li><li>Conduct and drive multiple extensive Proof of Concepts (PoCs) simultaneously, focusing on research, automation, and framework development.</li><li>Bring in the latest and greatest cloud-based solutions, ensuring the organization stays at the forefront of technology.</li><li>Experience or exposure to Generative AI, Large Language Models (LLM), and Agentic AI is highly desirable.</li><li>Highly technical and hands-on coding experience on multiple tech stacks related to Data Engineering and framework development on and for AWS Cloud.</li></ul> Essential Skills:<ul><li>15-18 years of experience as a Data Engineering professional in a data-intensive environment.</li><li>The individual should have strong analytical and reasoning skills in the relevant area.</li><li>Proficiency in AWS cloud services, specifically EC2, S3, Lambda, Athena, Kinesis, Redshift, Glue, EMR, DMS, Event Bridge, DynamoDB, IAM, Secret Manager, KMS, Step functions, SQS, SNS,</li><li>Experience in Cloud Foundation (CFN), Cloud Development Kit (CDK) and Software Development Kit (SDK).Exposure to MSK, Flink, Iceberg [good to have]</li><li>Cloud Watcher, User Notification, Appflow, Fargate, ECS, EKS, Airflow, Boto3, RDS, Sagemaker, IAM, , Cookie Cutter.</li><li>Excellent skills in Python-based framework development are mandatory.</li><li>Proficiency in SQL for efficient querying, managing databases, handling complex queries, and optimizing query performance.</li><li>Excellent automation skills are expected in areas such as:</li><li>Automating the testing framework and various test cases including unit, integration, functional tests, and mock-ups using tools such as PyPy, Pytest</li><li>Modularisation and automating the data pipeline and expediting tasks such as data ingestion and transformation using various tools like DBT.</li><li>API-based automated and integrated calls (REST, cURL, authentication & authorization, tokens, pagination, open Api, Swagger).</li><li>Implementing advanced engineering techniques and handling ad hoc requests to automate processes on demand.</li><li>Implementing automated and secured file transfer protocols like XCOM, FTP, SFTP, and HTTP/S.</li><li>Experience with Terraform, Jenkins, Teamcity and Artifactory is essential as part of DevOps. Additionally, Docker and Kubernetes are also considered.</li><li>Proficiency in building orchestration workflows using Apache Airflow.</li><li>Strong understanding of streaming data processing concepts, including event-driven architectures.</li><li>Familiarity with CI/CD pipeline development, such as Jenkins.</li><li>Extensive experience and understanding in Data Modelling, SCD Types, Data Warehousing, and ETL processes.</li><li>Excellent experience with GitHub or any preferred version control systems.</li><li>Expertise in data pipeline development using various data formats/types.</li><li>Mandatory knowledge and experience in big data processing using PySpark/Spark and performance optimizations of applications.</li><li>Proficiency in handling various file formats (CSV, JSON, XML, Parquet, Avro, and ORC) and automating processes in the big data environment.</li><li>Ability to use Linux/Unix environments for development and testing.</li><li>Should be aware of security best practices to protect data and infrastructure, including encryption/decryption, tokenization, masking, firewalls, and security zones.</li><li>Well-structured documentation skills and the ability to create a well-defined knowledge base.</li><li>Should be able to perform extreme engineering and design a robust, efficient, and cost-effective data engineering pipelines which are highly available and dynamically scalable on demand.</li><li>Enable the systems to effectively respond to high demands and heavy loads maintaining the high throughput and high I/O performance with no data loss.</li><li>Own and lead E2E Data engineering life cycle right from Requirement gathering, design, develop, test, deliver and support as part of DevSecOPS process.</li><li>Must demonstrate skills and mindset to implement encryption methodologies like SSL/TLS and data encryption at rest and in transit and other data security best practices.</li><li>Hands on work experience with data design tools like Erwin and demonstrate the capabilities of building data models, data warehouse, data lakes, data assets and data products.</li><li>Must be able to constructively challenge the status quo and lead to establish data governance, metadata management, ask the right questions, design with right principles.</li><li>Extensive experience in leading and managing large-scale data engineering teams and projects.</li><li>Proven track record of delivering high-impact data solutions that drive business value.</li><li>Ability to influence and drive change across the organization through data-driven insights and strategies..</li><li>Strong communication and presentation skills.</li><li>The individual should have strong analytical and reasoning skills in the relevant area.</li><li>One should possess attention to detail, ensuring data accuracy and reliability.</li><li>As part of teamwork, one should collaborate effectively with other stakeholders to achieve efficient outcomes.</li><li>One should be able to prioritize tasks and manage time efficiently.</li><li>The candidate should be committed to continuous learning.</li><li>Challenge status quo and demonstrate thinkers’ ability.</li></ul>Education Qualification:<ul><li>Bachelor’s degree or master’s degree in engineering in Computer Science/Information Technology</li></ul>

Calculate Moving Average	SQL	Easy
Predict Customer Churn	Machine Learning	Medium
A/B Test Significance	Statistics	Medium
Optimize Query Performance	SQL	Hard
Feature Importance Analysis	Machine Learning	Medium
Clean Missing Data	Python	Easy
Neural Network Architecture	Deep Learning	Hard
Calculate Cohort Retention	SQL	Medium
Bayesian Probability	Statistics	Easy
Recommend Similar Products	Machine Learning	Hard

Commonwealth Bank Interview Questions

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Commonwealth Bank Interview Questions

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Discussion & Interview Experiences

Discussion & Interview Experiences